Why is this throwing an invalid syntax error?

Question

I have been trying to solve 3sum on leetcode. The line ‘lower +=1’ (below the first triplets.append) is throwing an invalid syntax error but I have no idea why.

class Solution(object):
def threeSum(self, nums):
    if len(nums) < 3:
        return([])
    
    triplets = []
    
    nums = sorted(nums)
    
    for i in range(0, len(nums)-2):
        
        lower = i + 1
        upper = len(nums) - 1
        
        while lower < upper:
            
            s = nums[i] + nums[lower] + nums[upper]
            
            if s == 0:
                triplets.append((nums[i], nums[lower], nums[upper])
                lower += 1
            elif s < 0:
                lower += 1
            else:
                upper -= 1
    return(list(set(triplets))

Asked By: Steve

||

Source

Answer 1

The line

triplets.append((nums[i], nums[lower], nums[upper])

is missing a trailing ‘)’

Answered By: Seth Speaks

Answer 2

This code runs without issue – I commented the two places that needed extra parentheses to close unopen (.

I also indented the entire def but I wasn’t sure if that was just a product of your original copy-and-paste.

class Solution(object):
    def threeSum(self, nums):
        if len(nums) < 3:
            return([])
        
        triplets = []
        
        nums = sorted(nums)
        
        for i in range(0, len(nums)-2):
            
            lower = i + 1
            upper = len(nums) - 1
            
            while lower < upper:
                
                s = nums[i] + nums[lower] + nums[upper]
                
                if s == 0:
                    # this needed a closing paren
                    triplets.append((nums[i], nums[lower], nums[upper]))
                    lower += 1
                elif s < 0:
                    lower += 1
                else:
                    upper -= 1

        # and this also needed a closing paren
        return(list(set(triplets)))

# don't mind this - just adding something for local running
if __name__ == "__main__":
    print(Solution().threeSum([1,2,3]))

Answered By: wkl

Why is this throwing an invalid syntax error?

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